My first attempt to install 12.3.1 has failed, with a report of a kernel panic. Though I'm not sure whether it is the same issue as the iBoot panic mentioned before...? But I'm not keen to attempt again until i have identified this: panic(cpu 0 caller 0xfffffe00167b384c): watchdog timeout: no checkins from watchdogd in 94 seconds (96 total checkins since monitoring last enabled) Debugger message: panic Memory ID: 0x6 OS release type: User OS version: 21A559 Kernel version: Darwin Kernel Version 21.1.0: Wed Oct 13 17:33:01 PDT 2021; root:xnu-8019.41.5~1/RELEASE_ARM64_T6000 Fileset Kernelcache UUID: 3B2CA3833A09A383D66FB36667ED9CBF Kernel UUID: 67BCB41B-BAA4-3634-8E51-B0210457E324 iBoot version: iBoot-7429.41.5 secure boot?: YES Paniclog version: 13 KernelCache slide: 0x000000000e480000 KernelCache base: 0xfffffe0015484000 Kernel slide: 0x000000000eca8000 Kernel text base: 0xfffffe0015cac000 Kernel text exec slide: 0x000000000ed90000 Kernel text exec base: 0xfffffe0015d94000 mach_absolute_time: 0x59bab7cc38b Epoch Time: sec usec Boot : 0x624188b4 0x0002db60 Sleep : 0x624814e7 0x0005c77d Wake : 0x6248184c 0x000d26d6 Calendar: 0x62481c62 0x0006cbd6